This invention relates to a current squaring circuit for producing an output current having a magnitude proportional to the square of the magnitude of the input current applied thereto.
There are known electric devices performing the function of electrically squaring an electrical quantity, such as wattmeters employing differential thermocouples, squaring circuits utilizing a broken line approximation, and analog multipliers, etc. In such electric devices, the input and output have a narrow effective range and the operating range over which the output has a relative error less than 1% is only one or two decades.
Accordingly it is an object of the present invention to eliminate the disadvantages of the prior art practice as above described by the provision of a current squaring circuit having an effective range of about three decades for the input and about six decades for the output while being operative at a frequency equal to or higher than 100 kilohertz with a relative error maintained at about 1% over the entire effective range.
It is another object of the present invention to provide a new and improved current squaring circuit capable of compensating for differences in characteristics between the transistors used.